1. Field of the Invention
The present invention relates to a liquid crystal display device.
2. Discussion of the Related Art
Liquid crystal displays may have the characteristics of being light weight, slim, and low power. Liquid crystal displays are applied to portable computers such as note book personal computers, official automation devices, audio/video devices, and external/internal advertising display devices. The transparent type of liquid crystal display device which is the type most often used, displays the picture data by modulating the luminescence of the light incident from the backlight unit by controlling the electric field applied to a liquid crystal layer.
The liquid crystal display device includes a liquid crystal display module and a driving circuit for the liquid crystal display module. The driving circuit of the liquid crystal display module includes the following: a data driving circuit for supplying data voltages to the data lines of the liquid crystal display panel, a gate driving circuit for supplying a scan pulse to the scan lines of the liquid crystal display panel, and a timing controller for controlling the operating timing of the driving circuits. The timing controller is equipped with a control board and the ICs of the data driving circuit are mounted on a source PCB (Printed Circuit Board). A FPC (Flexible Printed Circuit) is located between the control board and the source PCB. Digital video data and the timing control signals are transmitted through the FPC. The control board is connected to the system board through an interface cable. A scaler converts the resolution of the video data according to the resolution of the liquid crystal display panel and sends the data to the control board.
The number of lines of the interface cable connecting between the system board and the control board is determined by the amount of the data and the clock signals to be sent. Typically, when the liquid crystal display device is in the Full-HD 120 Hz mode, the interface cable between the system board and the control board can have 48 lines if the type of interface that is applied is LVDS (Low-Voltage Differential Signaling). As mentioned above, even though the LVDS interface type is used, the interface cable still may have a lot of lines. Therefore, the number of connector pins used for connecting the interface cable to the system board and the control board may be a lot as well. Costs increase due to the number of interface cables and connectors used. Furthermore, due to the high frequencies being transmitted through the interface cable by the clock signal there is a high EMI (Electromagnetic interference) problem.
Recently, new interface types having lower EMI and fewer transmitting lines than those of LVDS interface types are being developed. However, until the conventional LVDS interface may be fully replaced with the new type interface, the newly developed interfaces and the conventional LVDS interfaces should be used contemporaneously. Therefore, there is a need to connect the newly developed interfaces with the conventional LVDS interfaces making them compatible with one another.